Investigations of the Stability of Pyrolysis Oil during High Temperature Treatment

Pyrolysis oil is produced from biomass when a feedstock is rapidly heated in a non-oxidizing environment during a short residence time. While pyrolysis oil is inexpensive, major issues prevent the facile use of this oil product ‘as produced’. Principally, since the rapid condensation results in a product not in thermodynamic equilibrium, the oil components continue to react until equilibrium is reached. Understanding how and why these reactions—including polymerization—occur in pyrolysis oil is important in designing treatments to stabilize or transform pyrolysis oil before further upgrading. Physical and chemical changes in pyrolysis oils are investigated as a function of temperature and time to simulate the aging process during storage. The effects of alcohol addition on pyrolysis oil stability during high temperature treatment are investigated. The pretreatment of pyrolysis oil with low-cost alcohols is promising prior to hydrotreating or catalytic cracking

Immobilization of Isocitrate Dehydrogenase on Mesoporous Silica Foam for Carbon Dioxide Capture

Carbon capture can be realized effectively through isocitrate dehydrogenase reaction and the reaction rate was strongly affected by the environmental parameters such as pH and temperature. Enzyme immobilization was conducted to improve the enzyme stability during the capture process. By simply adsorbing enzyme on the surface of mesoporous silica foam, enzyme stability against temperature, pH and shear stress was improved. The immobilization process can be completed in 5 mins, and 0.87 U enzyme activity was kept for each gram of immobilization material. After 10 cycles, more than 50 percent of enzyme activity remained. The reusability and improved stability made immobilized ICDH a better candidate for large-scale application of carbon capture

Catalytic Pyrolysis of Biomass and Polymer Wastes

Oil produced by the pyrolysis of biomass and co-pyrolysis of biomass with waste synthetic polymers has significant potential as a substitute for fossil fuels. However, the relatively poor properties found in pyrolysis oil—such as high oxygen content, low caloric value, and physicochemical instability—hampers its practical utilization as a commercial petroleum fuel replacement or additive. This review focuses on pyrolysis catalyst design, impact of using real waste feedstocks, catalyst deactivation and regeneration, and optimization of product distributions to support the production of high value-added products. Co-pyrolysis of two or more feedstock materials is shown to increase oil yield, caloric value, and aromatic hydrocarbon content. In addition, the co-pyrolysis of biomass and polymer waste can contribute to a reduction in production costs, expand waste disposal options, and reduce environmental impacts. Several promising options for catalytic pyrolysis to become industrially viable are also discussed.Article processing charges for this publication funded in part by the University of Oklahoma Libraries Open Access Fund.Ye

Size-selective Catalysis by Encapsulated Metal Nanoparticles

Supported metal nanoparticles (NPs) represent a large category of heterogeneous catalysts that are important for oil refinery, chemical production, and many emerging applications such as biomass conversion, hydrogen fuel cell, artificial photosynthesis, and electrocatalysis. A considerable amount of work has been devoted to the synthesis and characterization of supported metal NPs. However, supported NPs prepared by traditional methods, e.g. deposition-precipitation, ion exchange, electrostatic adsorption, hardly exhibit size-selectivity. Herein, we have developed a general protocol to encapsulate metal NPs into zeolites by atomic layer deposition (ALD) to force reactants diffuse through channels of zeolitic supports before they access metal NPs. Three pathways were investigated: (1) Induced ALD coating of metal NPs/support; (2) Area-selective ALD (AS-ALD) coating of metal NPs/support; (3) Using the intrinsic properties of supports. We have found AS-ALD coating of metal NP/zeolite can be used to attain the target nanostructures. The synthesized nanostructures with metal NPs fully coated and zeolite support (SAPO-34, ZSM-35, ZSM-5 and Beta) partially-coated exhibit high size-selective properties in hydrogenation reactions of olefins. It has appreciable activities for ethylene and almost no activity for the bulkier isobutylene. H2-D2 exchange reactions also proved the synthesized structure, where the coated silane/alcohol-Pt/ZSM-35 showed obvious lower activities than coated silane/alcohol-Pt/Beta because of hindered diffusion. Various techniques such as energy-dispersive X-ray spectroscopy (EDS), N2 physisorption, Transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR) have been used to characterize the target nanostructures. Compared to the existing methods, our proposed strategy is applicable to many types of metal NPs and zeolites

Immobilization of Isocitrate Dehydrogenase on Mesoporous Silica Foam for Carbon Dioxide Capture

Carbon capture can be realized effectively through isocitrate dehydrogenase reaction and the reaction rate was strongly affected by the environmental parameters such as pH and temperature. Enzyme immobilization was conducted to improve the enzyme stability during the capture process. By simply adsorbing enzyme on the surface of mesoporous silica foam, enzyme stability against temperature, pH and shear stress was improved. The immobilization process can be completed in 5 mins, and 0.87 U enzyme activity was kept for each gram of immobilization material. After 10 cycles, more than 50 percent of enzyme activity remained. The reusability and improved stability made immobilized ICDH a better candidate for large-scale application of carbon capture

Improvement of multiplex semi-nested PCR system for screening of rare mutations by high-throughput sequencing

The CRISPR/Cas9 system is an efficient gene-editing method, but it is difficult to obtain mutants for some specific species and special genome structures. A previously reported multiplexed, semi-nested PCR target-enrichment approach, which does not rely on transgenic technology, has been shown to be an effective and affordable strategy for the discovery of rare mutations in a large sodium azide-induced rice population. However, this strategy has the potential for further optimization. Here, we describe an improved multiplex semi-nested PCR target-enrichment strategy with simplified processing procedures, reduced false-positive rates and increased mutation detection frequency (1 mutation/73 Kb)